Wave-actuated load compensator

ABSTRACT

A wave-actuated floating load compensator having a chamber located substantially below the area of surface wave turbulence receives liquids, usually excess ballasting water or bilge water from a remotely disposed floating hull. A plurality of, preferably eight, reciprocally actuated pumping units is circumferentially disposed about the submerged chamber to ensure dynamic stability. A valve, provided on a chamber, meters the amount of fluid entering and the pumping units pump the fluid into the surrounding water. The valve and the pumping units thusly prevent inadvertent overloading of the compensator and its possible sinking. Having floats concentrically carried and guided on its associated pumping unit, eliminate costly seals and complicated linking mechanisms found in known devices.

United States Patent [72] Inventors William B. Mclean;

Edgar N. Rosenberg, both of San Diego, Calif.

[2|] Appl. No. 7,497

[22] Filed Feb. 2, 1970 [45} Patented July 27, 1971 [73] Assignee The United States of America as represented by the Secretary of the Navy [54] WAVE-ACTUA'I'ED LOAD COMPENSATOR 3,289,592 l2/l966 Franzreb 3,362,336 1/1968 Kaflca ABSTRACT: A wave-actuated floating load compensator having a chamber located substantially below the area of surface wave turbulence receives liquids, usually excess ballasting water or bilge water from a remotely disposed floating hull. A plurality of, preferably eight, reciprocally actuated pumping units is circumferentially disposed about the submerged chamber to ensure dynamic stability. A valve, provided on a chamber, meters the amount of fluid entering and the pumping units pump the fluid into the surrounding water. The valve and the pumping units thusly prevent inadvertent overloading of the compensator and its possible sinking. Having floats concentrically carried and guided on its associated pumping unit, eliminate costly seals and complicated linking mechanisms found in known devices.

PATENTED JUL27 I97! SHEET 1 OF 2 INVENTORS WILLIAM B. McLEAN BY EDGAR N. ROSENBERG THOMAS G. KEOUGH ERVIN F JOHNSTON ATTORNEYS PATENTEDJULZ'IIQTI SHEUZUFZ 3,595 189 INVENTORS WILLIAM B. McLEAN BY EDGAR N. ROSENBERG THOMAS G. KEOUGH ERVIN F. JOHNSTON ATTORNEYS WAVE-ACTUATEID LOAD COMPENSATOR STATEM ENT OF GOVERNM ENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION Contemporary offshore floating platforms are often provided with auxiliary pumps, used to maintain a preselected level of buoyancy by selectively transferring ballasting water. As is immediately apparent, employing a stationary fixed engine driving a centrifugal pump adds weight and, if duplicated per flotation unit, is unduly expensive. Using known wave-actuated pumping devices mounted on the platform has also proven to be an expensive undertaking, in addition to being relatively unreliable, since the wave displaceable floats, found in existing pumping devices, are prone to become battered against the flotation structures and become useless in time. An alternative to the aforementioned load-compensating systems is to periodically tow the platforms to a central pumping station to effect the water transfer operation, but this method is impractical. A need exists for a simple, reliable unit requiring little or no maintenance and supervision having mobility for use at widely separated spots.

SUMMARY OF THE INVENTION The present invention is directed to providing a floating wave-actuated load compensator, portable, and requiring little maintenance and supervision during operation. A large airtight chamber sized for buoying the compensator is disposed a distance below the area of surface wave action and has at least one valved inlet orifice and at least one outlet orifice. A plurality of reciprocably displaceable pumping assemblies is carried adjacent the chamber with separate ones of the assemblies actuated by a coaxially carried float imparting a reciprocable force to the pumping unit. Water is pumped from the interior of the chamber through the outlet orifice by each of the pumping units at a maximum rate determined by the current state of the sea. An inlet flow restricting valve controls the flow rate entering the chamber, the volume of the flow being transferred through hoses from remotely disposed, flooded ballasting chambers. The overall configuration of the liquid transfer apparatus including the method of supporting the motion. imparting floats requires little maintenance, eliminates contemporary cumbersome and complicated linkages, and requires little or no supervision during operation.

A prime object of the invention is to provide a highly reliable wave-actuated load compensator requiring little supervision.

Another object is to provide a load compensator constructed to maintain static stability while evacuating remotely disposed hulls.

Yet another object is to provide pumping units having no complicated seals or linkages greatly improving reliability.

A further object is to provide a completely portable load compensator operational wherever there is wave action.

Still another object is to provide a redundancy in pumping units ensuring load compensation in the event of possible partial failure.

These and other objects of the invention will become readily apparent from the drawings when taken with ensuing description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the invention operatively associated with a flotation platform.

FIG. 2 is a top view of the invention.

FIG. 3 is a sectional view generally taken along lines 3-3 in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, the invention is operatively connected to an offshore floating platform formed of a plurality of individual bottle-shaped flotation modules 11 each having, as schematically depicted, a module valve 11a or similar device for permitting the selective evacuation of an internally contained ballasting water chamber. Note here that the relative size of the invention is exaggerated with respect to the size of the module. A feeder line 12 places wave-actuated load compensator 15 in fluid communication with the flotation modules to permit their selective evacuation.

The wave-actuated load compensator is formed of two major components, those being a pressuretight vessel 20 defining a pressure chamber 21 and eight pumping assemblies 30. The pressuretight vessel is constructed of steel or fiber glass or similar high-strength material to internally provide a chamber having a substantial fluid capacity. Within the chamber, to prevent its inadvertent overflooding and sinking, watertight panels are included or a flotation material is contained in the chamber in keeping with contemporary boat designs calling for such materials as safety demands.

An inlet orifice provided through a valve 22 joins the interior of the chamber in fluid communication with the feeder line 12 and an extended stem portion 22a enables selective variation of the flow rate by an operator standing on platform 24. Selective flooding of the chamber further lowers it and the entire load compensator into the water to enable the pumping operation.

The platform, carried on a vertical extension of the chamber, or strut 23, journals the stem portion, in addition to being stressed to provide vertical support and guidance for the pumping assemblies. Although the strut is shown as being tubularly shaped, it is preferably designed having a minimal cross-sectional area to ensure a negligible reaction with surface wave turbulence to enhance the stability of the load compensator.

At the lower end of the pressuretight vessel, an outlet fitting 25 is mounted to pass the ballasting water received by line 12 to a common, annular-shaped feeder duct 26. The feeder duct is supported on the outer surface of the pressuretight vessel by a plurality of braces 26a and transfers ballasting water simultaneously to all the pumping assemblies.

Although the weight and location of the pressuretight vessel by itself tends to maintain the wave-actuated load compensator in a vertically stable relationship, increased stability is realized by either suspending a weight 16 from the pressuretight vessel by a triangular supporting member 17, or, simply, conventionally anchoring the load compensator by line.

Pumping assemblies 30 are designed to ensure higher reliability and each includes an elongate cylinder 31 having a thin wall, tubular cross-sectional configuration. Each cylinder is secured to the pressuretight vessel by a separate, radially extending frame member 31a having a portion circumferentially gripping the outer surface of the uppermost extension of the cylinder. Approximately, midway down each cylinder, an annular clamp-brace 31b further secures each cylinder and the lowermost extension of each of these cylinders is anchored to annular-shaped feeder duct 26 by a welded fitting 31c enclosing an opening 31d communicating with the feeder duct.

Above opening 31d, a disc-shaped one-way valve 32 is securely force fitted within each cylinder. Although FIG. 3 depicts the relative location of the one-way valve as being close to the welded fitting, the valve is optionally located higher in the cylinder. However, from a standpoint of maintenance and installation, location near the welded fitting has been found to be most expedient.

A similarly constructed disc-shaped piston 33 provided with a one-way valve arrangement is laterally disposed in the tube and is sized to permit a substantially sealed, longitudinally reciprocal motion within each cylinder.

l A pushrod 34, secured to each of the disc-shaped pistons, jaxially extends a considerable distance upwardly through each lcylinder passing an egress vent or outwardmost portion 31e to l be operatively disposed a considerable distance above the surface of the water. The great length of the pushrod being Iongitudinally contained within the considerable length of the cylinder, restricts the angular displacement of the pushrod from one inward side to the diametrically opposed inward side of end portion 312 to eliminate the necessity for providing a complicated and costly seal and linkage assembly on each of the disc-shaped pistons. By restricting the angular or rotational capability of the pushrod piston, damaging wear to both the piston and the inside surface of the cylinder is largely eliminated and, hence, longer service life and greater reliability are inherent.

The outwardmost extension of the pushrod is secured by bolting, welding, or equivalent method to the center of a round plate 35 peripherally mounting the apex portion of a tripod-shaped truss 36 at the tops of leg portions 36a. The base at leg portions 36b is secured to an individual barrelshaped float 37 provided with an axially extending bore 370 sized to permit a reciprocal, longitudinal motion along the outer surface of each elongate cylinder 31.

The length of the axially extending bore and its slightly larger diameter than the cylinder mechanically cooperates with the interconnected truss and pushrod to minimize angular canting of the piston within the cylinder. Thus, the manner of each floats being carried in a coaxial relationship on each cylinder further reduces linkage and sealing requirements to further enhance the load compensators overall reliability. Suitable lubrication or Teflon like liners between the cylinder and the floats is, of course, provided to eliminate wear.

The unique circumferentially, equaldistant-spaced arrangement of the individual pumping units positioned by the radially extending frame member, annular clamp-braces, and welded fittings coupled with the overall, elongate configuration of the load compensator affords a high degree of lateral stability in the most adverse states of sea, as well as does the minimal cross-sectional area, extending through the area of surface wave turbulence, presented by tripod-shaped trusses 36 and elongate cylinders 31.

In operation, the invention, not being anchored, is towed to the worksite. Connection of feeder line 12 between valve 22, and module 11a and adjusting the flow rate through valve 22, pass ballasting water to chamber 21. The water, fed through a fitting 25 to the annular-shaped feeder duct, is sucked by the vacuum created by the reciprocal displacement of the several disc-shaped pistons 33 to draw water into each elongate cylinder 31 (note the arrows in FIG. 3 showing water flow).

Wave action buoys up the plurality of floats to effect the reciprocal displacement of their connected pistons and an unsupervised water evacuation operation progresses. In a typical embodiment of the invention, the pumps expel water past each outwardmost portion 312 to the exterior of the elongate cylinder at a rate in excess of one-half gallon per stroke. With all eight floats displacing their interconnected pistons, over four gallons of water are evacuated per wave. Once the waveactuated load compensator is attached to a source of water wished to be transferred, no further attention need be given the compensator until the job is finished.

Although the preferred embodiment shows the chamber drawing the ballasting water, by the several pumping assemblies creating a sufficient vacuum within the pressuretight vessel to draw water from the lower level of the modules, a gravity fed water flow can be handled by the invention such as would be produced by shallow draft barges.

Construction of the compensator must take into consideration its operational environment, the sea. Noncorrosive materials and corrosion inhibiting coatings must be employed wherever possible to ensure the long operational life guaranit is therefore understood that within the scope of the disclosed inventive concept, the invention may be practiced otherwise than as specifically described.

What we claim is:

l. A floating, wave-actuated liquid transfer apparatus comprising:

means defining a chamber sized for buoying itself beneath the surface of wave action having at least one inlet orifice and at least one outlet orifice;

a plurality of pumping assemblies circumfcrentially carried on the chamber means in fluid communication with said outlet orifice, each including, an elongate cylinder joined at one end to said outlet orifice and longitudinally extending above the water surface tcrminating in an egress vent,

a reciprocable pump piston carried in each cylinder,

a pushrod connected to said piston coaxially reaching outwardly through said egress vent,

a float provided with a traverse bore configured for guiding said float in reciprocal, slidable longitudinal motion along the outer surface ofsaid cylinder, and

a follower connected to the outwardmost extension of said pushrod being sized to keep said float slidably adjacent within the extreme limits of said outer surface during said longitudinal motion; and

means restricting the liquid flow rate through said inlet orifice further settling said chamber means below said water surface bringing at least one said float in contact with said water surface ensuring reciprocal displacement by said wave action to pump said liquid from said chamber through at least one said egress vent.

2. An apparatus according to claim 1 in which the cylinders are configured to present a minimal lateral resistance to surface wave action to minimize instability.

3. An apparatus according to claim 2 further including:

ballasting means depending from said chamber means to en sure an orthogonal intersection between the paths of said longitudinal motion and said water surface for increasing reliability.

4 An apparatus according to claim 3 further including:

a strut member vertically extending from said chamber means through said water surface;

an annular bracket member carried on said chamber means connected to each said cylinder of said pumping assemblies; and

a frame member secured to said strut member having radially extending portions, cooperating with said bracket member to position said pumping assemblies in a circumferentially, equaldistantly spaced relationship to provide additional stability.

5. An apparatus according to claim 4 in which each said float is a barrel-shaped cylinder and said traverse bore is coaxially disposed and said follower is essentially a tripod-shaped truss having its apex secured to a separate said aftmost extension and the base of the truss is secured to the upward facing surface of each said barrel-shaped cylinder.

6. An apparatus according to claim 5 in which the restricting means is provided with a projection extending to said frame member permitting selective variation of said flow rate and is adapted for coupling to at least one feeder hose passing liquids from remotely disposed filled chambers. 

1. A floating, wave-actuated liquid transfer apparatus comprising: means defining a chamber sized for buoying itself beneath the surface of wave action having at least one inlet orifice and at least one outlet orifice; a plurality of pumping assemblies circumferentially carried on the chamber means in fluid communication with said outlet orifice, each including, an elongate cylinder joined at one end to said outlet orifice and longitudinally extending above the water surface terminating in an egress vent, a reciprocable pump piston carried in each cylinder, a pushrod connected to said piston coaxially reaching outwardly through said egress vent, a float provided with a traverse bore configured for guiding said float in reciprocal, slidable longitudinal motion along the outer surface of said cylinder, and a follower connected to the outwardmost extension of said pushrod being sized to keep said float slidably adjacent within the extreme limits of said outer surface during said longitudinal motion; and means restricting the liquid flow rate through said inlet orifice further settling said chamber means below said water surface bringing at least one said float in contact with said water surface ensuring reciprocal displacement by said wave action to pump said liquid from said chamber through at least one said egress vent.
 2. An apparatus according to claim 1 in which the cylinders are configured to present a minimal lateral resistance to surface wave action to minimize instability.
 3. An apparatus according to claim 2 further including: ballasting means depending from said chamber means to ensure an orthogonal intersection between the paths of said longitudinal motion and said water surface for increasing reliability. 4 An apparatus according to claim 3 further including: a strut member vertically extending from said chamber means through said water surface; an annular bracket member carried on said chamber means connected to each said cylinder of said pumping assemblies; and a frame member secured to said strut member having radially extending portions, cooperating with said bracket member to position said pumping assemblies in a circumferentially, equaldistantly spaced relationship to provide additional stability.
 5. An apparatus according to claim 4 in which each said float is a barrel-shaped cylinder and said traverse bore is coaxially disposed and said follower is essentially a tripod-shaped truss having its apex secured to a separate said aftmost extension and the base of the truss is secured to the upward facing surface of each said barrel-shaped cylinder.
 6. An apparatus according to claim 5 in which the restricting means is provided with a projection extending to said frame member permitting selective variation of said flow rate and is adapted for coupling to at least one feeder hose passing liquids from remotely disposed filled chambers. 